This is physics, electricity. I'll break it down for you, very easy: you have to use the formula V=IR where V= voltage in volts (V) I= current in Amperes (A) R= resistance in ohms (Ω)
so what you require is I, current there you have to rearrange the formula to subject current; I=V/R =9/5= 1.8Ω (ans)